1. Field of the Invention
The present invention relates to a controller for a laser beam printer and, more particularly, to a system for controlling the arrangement of a print pattern in a page memory.
2. Description of the Prior Art
In a printer according to the prior art, in which a print pattern is edited and printed for each page, the printing width in the direction of a line is determined by the effective printing width of the printing unit of the printer, thus making it impossible to print a line longer than the effective printing width.
FIG. 1 shows the construction of a laser beam printer. This printer is connected with a host computer 100 and a printer controller 200 and is equipped with a laser oscillator 301, a laser modulator 302, a reflecting mirror 303, a rotary mirror 304, a focusing lens 305, a photosensitive drum 306 and a developer 307.
The coded printing information fed from the host computer 100 is converted into a print pattern and edited by the printer controller 200, and this print pattern is fed as an image signal to the laser modulator 302. On the other hand, the laser beam coming from the laser oscillator 201 is turned on and off by the laser modulator 302 in a manner to correspond to the white and black of the print pattern and is guided onto the rotary mirror 304 by the reflecting mirror 303. The beam thus reflected is focused by the focusing lens 305 to form a latent image on the photosensitive drum 306. The latent image thus formed on the photosensitive drum 306 is developed into a visible image by the developer 307 and is transferred to a sheet of print paper, thus completing the printing operation.
It is apparent that the printing width of the printer for one line cannot exceed the length of the photosensitive drum.